Which of the following best explains why scientists use space probes to collect data on Mars? Space probes are used to explore places that are too distant for telescopes to see. Space probes are used to explore distant galaxies because they are too far away for satellites to see. Space probes are used to explore places where Earth's atmosphere does not affect signals. Space probes are used to explore places that would be too dangerous for astronomers.

Female luna moths (actias luna) attract males by emitting chemical signals that spread through the air. a male hundreds of meters away can detect these molecules and fly toward their source. the sensory organs responsible for this behavior are the comblike antennae visible in the photograph shown here. each filament of an antenna is equipped with thousands of receptor cells that detect the sex attractant. based on what you learned in this chapter, propose a hypothesis to account for the ability of the male moth to detect a specific molecule in the presence of many other molecules in the air. what predictions does your hypothesis make? design an experiment to test one of these predictions.